P1234: REAL-WORLD EXPERIENCE OF OUTCOMES WITH GLOFITAMAB SALVAGE THERAPY FOR RELAPSE/REFRACTORY B-CELL LYMPHOMA IN TAIWAN: MINIMAL SAFETY CONCERN WITH HEPATITIS B REACTIVATION
Authors: S.-J. Wu, C.-K. Liao, Y.-W. Wang, M.-C. Wang
Journal: HemaSphere (2022)

Background: Glofitamab, a T-cell-engaging bispecific antibody (Ab) with a novel 2:1 configuration conferring robust bivalency for CD20 and monovalency for CD3, has recently shown promising activity in its phase I/II trial as a salvage therapy in various major subtypes of B-cell lymphoma. Few studies, however, have described the use of glofitamab in a real-world clinical setting. Aims: We aimed to depict the efficacy and safety profiles of glofitamab as a salvage therapy for patients with diffuse large B-cell lymphoma (DLBCL) and other subtype of B-cell lymphoma in the real-world setting with a special focus on the risk of hepatitis B virus (HBV) reactivation. Methods: The clinical data of patients with DLBCL or other B-cell lymphomas who had received ≥3 lines of prior therapies and received glofitamab salvage therapy in a compassionate use program in Nov. 2020 - Dec. 2021 were retrospectively analyzed. The treatment protocol included obinutuzumab pretreatment 1000mg given 7 days before the first glofitamab dose, followed by step-up dose of glofitamab administration: 2.5mg on Day 1 and 10mg on Day 8 of cycle 1, and then 30mg on Day 1 of cycle 2-12 (21-day cycles). Results: As of the end of 2021, 26 patients from two medical centers in Taiwan, 11(43%) of whom were females, were enrolled. Among them, 18 were diagnosed with de novo DLBCL, 3 with transformed large B-cell lymphoma, and 5 with other subtypes of B-cell lymphoma. The median age was 57 years (26-75). Among the 18 cases with de novo DLBCL, 10(56%) had non-germinal center subtype, and 9(50%), double-hit/triple-hit lymphoma. Extra-nodal lesions were observed in 12(46%) patients, and 7(27%), marrow involvement. Elevated LDH levels occurred in 15 (58%) patients. Median prior therapies were 5 (3–10) with 24(92%) patients having received ≥4 prior therapies. All patients had received prior rituximab therapy, 6(23%), autologous or allogeneic stem cell transplantation (SCT), and 9(35%), polatuzumab salvage. Nineteen (79%) patients were refractory to their most recent regimen. Median cycles of glofitamab treatment were 5 (1-12). With the median follow-up of 9 months, the median overall survival was 6 months. The overall response and complete response rates were 50% and 23%, respectively. The remissions are durable (Figure 1): among 13 responders, 8 are continuing the treatment, 1 finished the planned 12 cycles of therapy, 1 had consolidated autologous SCT in remission status, and 2 passed away because of infections in remission status; only one case had disease relapse after achieving remission. No case has had disease progression after achieving an initial response. Cytokine releasing syndrome (CRS) occurred in 15(58%) patients; most of them occurred in the initial two cycles and were mostly of grade 1/2 severity except two cases (8%) with grade 3 CRS, both resulted from transaminitis. No grade 4/5 CRS, neurological toxicity, or fatal toxicity was observed. In terms of HBV infection, 7 patients were HBs antigen(+) and 6 of them had concurrent prophylactic HBV therapy during glofitamab treatment, whereas 11 patients were anti-HBc antibody(+)/HBs antigen(-) and 2 of them received prophylactic HBV therapy. No HBV reactivation event was observed in this cohort of patients. Image:Summary/Conclusion: In the real-world setting, glofitamab remains an effective salvage treatment for patients with heavily pretreated relapse/refractory DLBCL and B-cell lymphomas. No new safety issues were observed. With optimal prophylaxis, the risk of HBV reactivation would not be of concern during glofitamab treatment.